A system for automatically testing properties

Abstract

A test system was developed at Caterpillar to automatically measure the static stiffness as well as complex stiffness and phase angle of rubber mounts used for support, and for noise and vibration isolation in our vehicles. The system consists of a load frame with a hydraulic cylinder that applies load to the mount and an instrumentation and control system interconnected with a personal computer. The computer acquires load and displacement measurements from the mount through an analog-to-digital converter connected to computer controllable signal conditioners. The computer acts on these signals and controls a programmable function generator, which supplies a command signal to a hydraulic servo controller that controls load or displacement of the mount. The test system software allows the operator to configure the test through form fill-in menus and special function keys. Following setup, the system automatically runs the tests and prints or plots results to the CRT and optionally to the system printer. Additionally, the system allows the operator to specify characteristics of the sensors being used and guides the operator through calibration of the signal conditioners.